Method of drawing sheet glass



Aug. 19, 1924. 1,505,584

H. S. CAMPBELL METHOD OF DRAWING SHEET GLASS Filed Feb. 12, 1919 atentedAug. 19, 1924.

UNITED STATES HUDSON s. owl-BELL, or onnnxsnune, wEsr vnmmriei.

METHOD or DRAWING SHEET GLASS.

Application filed February 12, 1919. Serial No. 276,691. I

To all whom it may concern:

Be it known that HUDSON S. CAMPBELL, a citizen of the United States, aresident of Clarksburg, in the county of Harrison and State of WestVirginia, has invented a new and useful Improvement in Methods of-Drawing Sheet Glass; and he does hereby declare the following to be afull, clear, and exact description thereof.

My invention relates particularly to a method of drawing glass in sheetform.

The object of my invention is to provide a method of drawing sheetglass, in which the drawing operation is a continous one and the glassis so supported in the operation as to keep it spread or taut, thusinsuring a perfectly flat piece of glass while, at the same timeprovision is made for severing the glass in sheets of any suitablelength as it is being formed.

In the accompanying drawing, I have illustrated apparatus suitable tocarrying out my improved method in which Figure l is a view of a portionof a suitable furnace with a forehearth or a dog-house extension shownpartly broken away with the drawi g apparatus arranged therein; Figure 2is a section on the line 2-2 on Figure 1; Figure 3 is an enlarged viewshowing the manner in which the sheet is severed, and Figs. 4, 5, and 6are perspective views of the cutting and gripping blocks.

In the drawing the numeral 2 designates a suitable furnace with theforehe-arth or dog-house 3 into which the glass 2 flows from the furnace2. In order to cut 05 to some extent, the heat of the furnace from thearea from which the glass sheet is drawn, any suitable shielding device4 may be em lo ed.

p be upper and lower shafts 5 and 6 are arranged in pairs parallel toeach other in suitable bearings and mounted on said shaft at each endthereof are the sprocket wheels 7 and 8 respectively.

Chains 9 and 10 are mounted on said sprocket wheels and power isprovided for driving said chains in opposite directions,

as indicated by the arrows Fig. 1. The links of the chain are providedwith gripping blocks 11, with the serrations or teeth, 12, formedtherein as shown Fig. 6.-

At intervals on the chains 9 are the bars 13, which extend from onechain to the other, said bars having the fiat-faced portions 14 and theserrated portions 15.

,The chains 10 carry the bars 16 which extend from one cham to theother, and said bars are provided with the knife 17, and the serrations17*. The bars 13 and 16 are so arranged that as the said chains travel,said bars will come into register with each other at the point in linewith the lower shaft 6, or before said bars leave the peripheries of thelower sprocket wheels, the knife like edge 17 co-operating with the fiatface 14 of the bar, 13, to sever and at the same time grip the lasticglass as clearly indicated in Fig. 3. y having these bars co-operate inthis way before leaving the peripheries of the lower sprocket wheels, aresistance is afiordedto take up the thrust caused by the severing andgripping of the glass at this point, as will more fully here,- inafterappear.

In carrying. out my improved method by the apparatus above described,the glass is first lifted from the supply of molten glass in theforehearth 0r dog-house by lowering a suitable bait and lifting theglass up between the chafts 5 and 6 until it is in a position for thebars 13 and 16, which by coming in contact with each other, savers andgrips the succeeding sheet simultaneously at any point desired below theoriginal bait used for starting the draw, and the serrations on thelower part of the bars 13 and 16, which extend clear across the sheet,entering into the plastic glass, makes the grip for the continuous draw.This preliminary lifting of the glass by the bait has not beenillustrated, as there are many dif ferent forms of baits suitable forthis purpose, and this preliminary step forms no part of my presentinvention.

As soon as the gripping bars 13 and 16 take hold of the sheet the glasswill be kept moving or continue to be drawn by the operation of myapparatus and the sprocket wheels being geared together, the serrationsin blocks 13 and 16 act to replace the bait and operate as a bait untilsuch time as another set of said bars '13 and 16 come into place orcontact with the sheet of glass which is being drawn. The chains 9 and10 and side gripping blocks 11 carried thereby will travel at a uniformrate of speed and said blocks will be of a size only to extend for aboutan inch or so on both edges of the sheet, the intervening glass will besmooth and even and the drawing operation will be continuous, as long asthe sprocket in this manner, kee perfectly flat sheet is thus insured.

The sheet thus formed is severed and simultaneously the succeeding sheetregripped, while soft or plastic and this is done by the knife-bars 16,co-operating with the supporting bars 13. This severing accordinglytakes place down adjacent to the point of draw and the knife block andsupporting blocks are timed to come into register with each other,preferably before the blocks leave the peripheries of the lowersprockets, or in line with the shafts, so that the blocks are supportedagainst thrust during the severing and re-gmpping operation. This isclearly indicated in Figures 1 and 3 of the drawing where the knife edge17 is shown as having forced its way into the plastic sheet of glass andbefore the glass has hardened or set. This knife edge 17 cooperates withthe flat face 14 of the block 13 and the knife, b pressing against the.smooth face 14 of the block 13 will sever the glass at this point, andby reason of the serrations, 15 and 17- on blocks 13 and 16, the grip onthe succeeding sheet will be had below the point of severing,simultaneously with the severing and the glass will keep on travelingupward until the next set of severing and gripping bars 13 and 16 comeinto play to cut off one sheet and support the next sheet and continueits'upward movement, thus making a continuous draw. This is madepossible by the fact that the severing and gripping takes place at allpoints along the width of the sheet at the same time.

By the expression severing the glass as used both in the specificationand claims, I mean either the complete separation of the glass from themain body or such a separation as will leave the sheet connected to themain body only by a thin film, so that when the sheet passes above theapparatus, by bending the sheet at the point of severance, the sheetwill be detached from the main body of glass.

By my invention I provide for the drawing of sheet glass continuouslyand for the severing and simultaneously gripping of the succeeding sheetof the glass while it is still in its plastic or soft condition, therebyforming sheets of any desired length, and as the glass is only grippedalong its edges 1 and at its top edge during the drawing, only theportions so gripped is waste. As the intervening glass does not come incontact with any rolls or supporting device, the surface of the glasshas a very high finish and contains none of the defects due to theflattening operation required in the manufacture of glass by thecylinder process, which operation mars, to a more or less degree, one orboth surfaces of the glass. The glass is formed of any desired width orthickness and when introduced into the annealing oven it comes out witha perfectly annealed fire-polish on both sides of the sheet due to thefact that the glass during this formation is not subjected to anyrolling or flattening operation which will cause an uneven temperaturecondition due to defects caused by such rolling or flattening, and hencean imperfect annealing.

I prefer to make the bars 13 and 16 as well as the gripping blocks 11 ofcarbon such as set forth and claimed in an application filed by me onthe 8th day of August, 1919, Serial No. 316,109.

What I claim is:

1. The method of forming sheets of glass consisting in drawing the sheetcontinuously from a bath of molten glass, severing the glass,simultaneously gripping the succeeding sheet along its top edge, andgripping its side edges below the point where the first gripping occursto keep it spread taut.

2. The method of forming sheets of glass consisting in drawing the sheetcontinuously from a bath of molten glass, severin the glass, grippingthe succeeding sheet simultaneously with the severing Just below thepoint of severing, and gripping the side edges of the sheet at intervalsto keep the sheet taut, all while in a plastic condition.

In testimony whereof, I, the said HUDSON S. CAMrBELL, have hereunto setmy hand.

HUDSON S. CAMPBELL.

Witnesses:

C. W. VANNoR'r, CHARLES Lone.

